
Each opponent can't cast instant or sorcery spells during that player's next turn.
Sphinx's Decree has 2 printings, first in Rivals of Ixalan (2018). EDHREC ranks it #23,388 among Commander cards. It appears most in Azor, the Lawbringer decks (20 on EDHREC). It has 1 official ruling.
Deck counts from EDHREC.
Cards that show up in the same decks on EDHREC.